Herb & supplement monograph

Boxwood Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by ·Updated July 2026
What is this page for?

First and foremost: how Boxwood interacts with medications. The heart of this page is the interaction list — every drug Boxwood is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Boxwood is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Boxwood Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Boxwood drug interaction appears low for most people, since every listed interaction is theoretical and none has been confirmed in humans. No interactions are rated major, and all of them rest on lab research alone rather than studies in people.

Interactions deserving the most attention

The combinations most worth knowing about involve cholinergic drugs and anticholinergic drugs. Lab studies suggest boxwood may block an enzyme that breaks down acetylcholine, a chemical messenger in the nervous system. In theory, that could add to the effects of cholinergic medicines and raise the chance of side effects, or work against anticholinergic medicines and make them, or boxwood, less effective. Neither effect has been shown to happen in people.

What the rest of the list means

The long list of medications comes down to just these two broad drug families, so the large number does not mean each combination carries its own proven risk. These are predicted effects based on how boxwood behaved in laboratory tests, and there is no human evidence yet that they cause meaningful problems.

Check your medications against Boxwood

Based on HelloPharmacist’s Boxwood interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Boxwood

219 medications have a known interaction with Boxwood, graded by severity. Select any drug for the full evidence-based detail.

2,830 drugs
AcepromazineAtravet› Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, PhenylephrineHycomine Compound› Acetaminophen, Caffeine, PyrilamineMidol Max Strength Menstrual› Acetaminophen, Chlorpheniramine Maleate, Dextromethorphan HbrVicks Formula 44M Cough, Cold & Flu Relief› Acetaminophen, Chlorpheniramine, Codeine, PhenylephrineColrex› Acetaminophen, Chlorpheniramine, DextromethorphanCoricidin II Extra Strength Cold and Flu› Acetaminophen, Chlorpheniramine, Dextromethorphan HydrobromideCoricidin HBP Maximum Strength Flu› Acetaminophen, Chlorpheniramine, Dextromethorphan, PhenylpropanolamineMulti Symptom Cold Relief› Acetaminophen, Chlorpheniramine, Dextromethorphan, PseudoephedrineChildren's Tylenol Cold Plus Cough, Tylenol Cold Ex Strength› Acetaminophen, Chlorpheniramine, Guaifenesin, Phenylephrine, SalicylamideRhinogesic GG› Acetaminophen, Chlorpheniramine, PhenylephrineAlka-Seltzer PLUS, Histex SR, Protid› Acetaminophen, Chlorpheniramine, Phenylephrine, SalicylamideRhinogesic, Rhinogesic JR› Acetaminophen, Chlorpheniramine, PhenylpropanolamineAlumadrine, Conex, Sinadrin Max Strength, Sinulin› Acetaminophen, Chlorpheniramine, Phenylpropanolamine, OpiumHista-Derfule› Acetaminophen, Chlorpheniramine, Phenylpropanolamine, PhenyltoloxamineNorel Plus› Acetaminophen, Chlorpheniramine, PseudoephedrineAlka-Seltzer PLUS Liquid Gels, Children's Tylenol Cold, Codimal, Comtrex, Extra Strength Tylenol Allergy Sinus, Lorsin +3 more› Acetaminophen, Codeine, DoxylamineMersyndol› Acetaminophen, Dextromethorphan, Doxylamine, PseudoephedrineVicks NyQuil› Acetaminophen, Dextromethorphan, Phenylpropanolamine, PyrilamineTheracaps› Acetaminophen, DiphenhydramineTylenol PM, Tylenol PM Ex Strength› Acetaminophen, Diphenhydramine, PseudoephedrineChildren's Tylenol Allergy, Cold Control, Contac Night Allergy Relief› Acetaminophen, Doxylamine, PseudoephedrineEx Strength Tylenol Sinus Nighttime› Acetaminophen, Pamabrom, PyrilamineMidol Max Strength PMS, Pamprin, Pamprin ES› Acetaminophen, Phenylephrine, ChlorpheniramineSuper Cold Tabs› AcetylcholineMiochol-E› Aclidinium BromideTudorza Pressair› Aclidinium Bromide, Formoterol Fumarate DihydrateDuaklir Pressair› Aerosphere Budesonide, Formoterol Fumarate, GlycopyrrolateBreztri› AmantadineGocovri, Osmolex ER, Symmetrel› Ambenonium ChlorideMytelase›
Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each drug listed above links to the full report for that exact Boxwood combination — clinical detail, likelihood, evidence level, and citations.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
The big picture

The kinds of drugs Boxwood affects

Every type of medication (drug category) Boxwood is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 2 drug categories Boxwood interacts with
Anticholinergic DrugsCholinergic Drugs
Anticholinergic Drugs

Evidence from in vitro research suggests that boxwood extract can inhibit acetylcholinesterase activity. Theoretically, concurrent use of anticholinergic drugs and boxwood might decrease the effectiveness of boxwood or the anticholinergic agent.

Likelihood Possible Evidence D
Cholinergic Drugs

Evidence from in vitro research suggests that boxwood extract can inhibit acetylcholinesterase activity. Theoretically, concurrent use of boxwood with other cholinergic drugs might have additive effects and increase the risk of cholinergic side effects.

Likelihood Possible Evidence D
Monograph

Boxwood: Uses, Safety & Side Effects

Medically reviewed by · Reviewed July 2026 ·
The bottom line

Boxwood is an evergreen shrub whose leaves have been used in folk medicine, most notably in some early studies looking at HIV. The whole plant is toxic, so only processed extracts are used, and solid evidence for any health benefit is very limited. Because of real safety concerns, talk with a pharmacist or doctor before trying boxwood.

Boxwood
Scientific name
Buxus sempervirens
Family
Buxaceae
Part used
Leaves (processed into extracts)
Common forms
Capsules, liquid extracts, tinctures
People commonly use it for
  • HIV/immune support
  • Malaria
  • Arthritis
  • Diabetes
  • Skin conditions
  • Fever

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance
OverallUse caution

The raw plant is toxic; only processed extracts are used and safety data are limited.

PregnancyLikely Unsafe

When the whole leaf is used orally; avoid using. There is insufficient reliable information available about the safety of boxwood leaf extract when u...

Read the full pregnancy detail
BreastfeedingLikely Unsafe

When the whole leaf is used orally; avoid using. There is insufficient reliable information available about the safety of boxwood leaf extract when u...

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Boxwood (Buxus sempervirens) is a slow-growing evergreen shrub or small tree that many people know from gardens and landscaping, where it is often trimmed into hedges. It grows in parts of Europe, North Africa, and western Asia, and is widely planted elsewhere.

In traditional medicine, the leaves were used to treat fevers, malaria, and other complaints. Today, boxwood is most talked about as a processed leaf extract that has been studied in a small way for immune support, including in people with HIV. Because the whole plant is poisonous to humans and animals, only carefully prepared extracts are intended for use.

How it works

Boxwood leaves contain a group of natural compounds called steroidal alkaloids, along with other plant chemicals. Laboratory studies suggest some of these compounds may affect immune cells or have antimicrobial activity.

Researchers have proposed that certain extracts might influence the immune system, but the exact way boxwood would work in the body is not well understood. Most of this is based on test-tube and animal research, which often does not translate into real benefits or safety for people.

Effectiveness

Does Boxwood work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by .

Evidence overview · 1 use evaluated
1 Insufficient evidence
How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.
2Likely EffectiveGood evidence, though not yet conclusive.
3Possibly EffectiveSome evidence suggests a benefit.
4Possibly IneffectiveSome evidence it may not help.
5Likely IneffectiveFairly strong evidence it doesn’t help.
6IneffectiveStrong evidence it doesn’t work.
7Insufficient Reliable Evidence to RateToo little research to say either way.

For Boxwood, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 1 condition — evidence insufficient to rate
Insufficient Reliable Evidence To Rate HIV/AIDS
Rating & evidence shown verbatim from Natural Medicines

There is preliminary evidence that a specific boxwood leaf extract (SPV30) 990 mg per day might delay disease progression in HIV-infected patients. It seems to delay decreases in CD4 cell counts, increases in viral load, and/or progression to AIDS in asymptomatic patients with CD4 counts greater than 350 cells per microliter and a relatively low viral load. A higher dose of 1980 mg per day does not seem to be effective, possibly due to oxidative stress induced by flavonoids in the extract.

Sources Ref 5643

Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.

Safety & precautions

The whole boxwood plant is toxic if eaten, including the leaves, bark, and seeds. This is why only specially processed extracts are used, and why you should never make your own preparation from garden boxwood.

Because reliable human safety data are limited, anyone with a chronic illness, a weakened immune system, or who takes regular medication should speak with a doctor or pharmacist first. People with liver or kidney problems should be especially careful.

Pregnancy and breastfeeding: There is not enough information to consider boxwood safe, and the plant is toxic. To be safe, avoid boxwood if you are pregnant or breastfeeding.

Side effects

Because the plant is poisonous, swallowing raw leaves or improperly prepared products can cause serious poisoning, with symptoms such as nausea, vomiting, diarrhea, stomach pain, dizziness, and, in severe cases, seizures or breathing problems.

Even with processed extracts, milder side effects like stomach upset are possible, and the full side-effect profile in humans is not well known. Stop using boxwood and seek medical care right away if you feel unwell after taking it.

Boxwood: Reported Adverse Effects

Documented safety reports on Boxwood from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

Orally, boxwood leaf extract seems to be well tolerated. However, ingestion of whole boxwood leaf can cause serious side effects including vomiting, diarrhea, severe colonic spasms, paralysis, and death secondary to asphyxiation.

Topically, the fresh plant and wood can cause allergic contact dermatitis.

When inhaled, the wood dust can cause rhinoconjunctivitis and bronchitis.

  1. Durant J, Chantre P, Gonzalez G, et al. Efficacy and safety of Buxus sempervirens L. preparations (SPV30) in HIV-infected asymptomatic patients: a multicentre, randomized, double-blind, placebo-controlled trial. Phytomedicine 1998;5:1-10.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Carballada F, Prat M, Núñez R, et al. Allergy to boxwood. J Investig Allergol Clin Immunol. 2014;24(5):359-61.
Reports by condition
Acute bronchitis Immunologic

Occupational exposure to boxwood dust might cause allergic symptoms. In a case report, a 52-year-old male experienced symptoms such as rhinoconjunctivitis and bronchitis following occupational exposure to boxwood wood dust. Cases of allergic contact dermatitis to fresh boxwood leaves and a boxwood recorder have also been reported.

  1. Carballada F, Prat M, Núñez R, et al. Allergy to boxwood. J Investig Allergol Clin Immunol. 2014;24(5):359-61.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. van Neer, F. J. and van Ginkel, C. J. Allergic contact dermatitis from a boxwood recorder. Contact Dermatitis 1997;36(6):305.
Diarrhea Gastrointestinal

Orally, ingestion of whole boxwood leaf can cause serious side effects including vomiting, diarrhea, and severe colonic spasms. The extract, however, does not seem to have these effects.

  1. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  2. Durant J, Chantre P, Gonzalez G, et al. Efficacy and safety of Buxus sempervirens L. preparations (SPV30) in HIV-infected asymptomatic patients: a multicentre, randomized, double-blind, placebo-controlled trial. Phytomedicine 1998;5:1-10.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

Dosing

There is no well-established or standardized dose of boxwood for any condition. The strength and quality of commercial extracts can vary a lot from product to product.

If you choose to use a boxwood product, follow the directions on the label and do not exceed them. Never use leaves or material from garden boxwood, since the raw plant is toxic. Check with a pharmacist or doctor before starting, especially if you take other medicines or have a health condition.

Pregnancy & Breastfeeding

Boxwood & Pregnancy

Likely Unsafe

When the whole leaf is used orally; avoid using. There is insufficient reliable information available about the safety of boxwood leaf extract when used during pregnancy and lactation; avoid using.

  1. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

Boxwood & Breastfeeding

Likely Unsafe

When the whole leaf is used orally; avoid using. There is insufficient reliable information available about the safety of boxwood leaf extract when used during pregnancy and lactation; avoid using.

  1. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

© 2026 Therapeutic Research Center

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 6 references that drive our Boxwood monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Durant J, Chantre P, Gonzalez G, et al. Efficacy and safety of Buxus sempervirens L. preparations (SPV30) in HIV-infected asymptomatic patients: a multicentre, randomized, double-blind, placebo-controlled trial. Phytomedicine 1998;5:1-10. DOI
  4. Orhan, I., Sener, B., Choudhary, M. I., and Khalid, A. Acetylcholinesterase and butyrylcholinesterase inhibitory activity of some Turkish medicinal plants. J Ethnopharmacol 2004;91(1):57-60. PubMed
  5. van Neer, F. J. and van Ginkel, C. J. Allergic contact dermatitis from a boxwood recorder. Contact Dermatitis 1997;36(6):305.
  6. Carballada F, Prat M, Núñez R, et al. Allergy to boxwood. J Investig Allergol Clin Immunol. 2014;24(5):359-61.
Keep reading

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Brand directory

Brands that make products with Boxwood

2 brands in our database make a supplement containing Boxwood.

Product directory

Supplement products with Boxwood

7 products in our database contain Boxwood. Open any to see its full ingredient list and every drug interaction we check.

Pharmacist Counseling Corner

Boxwood: Common Questions

What is Boxwood used for, and does it work?
People use Boxwood for a range of reasons, but according to the Natural Medicines database the current clinical evidence is insufficient to confirm it works for the specific conditions it has been studied for. See the graded list on this page, and talk to your pharmacist or doctor before relying on it for any condition.
Does Boxwood interact with prescription medications?
Yes. We list 219 medications with a known interaction with Boxwood. Use the checker above to see how Boxwood interacts with a specific drug.
How are Boxwood interactions rated?
Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.
Is it safe to take Boxwood with my medications?
It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.
Where does this Boxwood interaction information come from?
Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.
What is Boxwood used for?
People have used Boxwood leaf extracts for immune support (including in HIV), malaria, fever, arthritis, and diabetes. Strong scientific proof is lacking for all of these uses.
Is Boxwood safe to take?
The whole plant is toxic, so only specially processed extracts are used, and even then human safety data are limited. Talk with a pharmacist or doctor before trying it.
Can I make Boxwood tea from my garden shrub?
No. Garden Boxwood leaves are poisonous and can cause serious illness if eaten or brewed. Never make your own Boxwood preparation.
Is Boxwood safe during pregnancy or breastfeeding?
No reliable safety information exists, and the plant is toxic, so Boxwood should be avoided during pregnancy and breastfeeding.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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